Method of making insertible saw-teeth



(No Model.)

, W. HAWKINS.

7 METHOD OF MAKING INS-ERT IBLE SAW TH. No. 280,617. Patente My .3, 1883.

r1; 7 Fig 9V.

Fig? '11 Wffnesses:

' the city and county of San Francisco, in the ings.

, tion of this excess of metal forward to folm sponding parts in all the figures where they V UNITED STATES PATENT OFF CE;

WILLIAM HAWKINS, OF SAN FRANCISCO, CALIFORNIA.

SPECIFICATION formingpart of Letters Patent No. 280,617, dated July 3, 1383.

Application filed September 27, 1881. (No model.)

To all whom, it may concern Be it known that I, WILLIAM HAWKINS, of

State of California, have invented an Improved Method of Manufacturing Inserted Saw-Teeth; and I do hereby declare that the following is a full, clear, and exact description thereof, reference being had to the accompanying draw- My invention relates to an improved method or process of forming insertible saw teeth from steel-plate. I

It consists in, first,'cutting out from suitable stock a blank in which is provided an excess of metal breadthwise and a deficiency lengthwise in the sectional area of the head as com pared with the finished'tooth to be produced; and, secondly, subjecting this blank to a continuous rolling pressure from heel to point edgewise in such manner as to throw a porthe point, to draw and distribute another portion backward and downward into the neck, or that portion of the toothwhere the head springs from the shank, and condense the remaining part into the head to produce required shape and increased thickness along the head and point of the tooth with uniform results in the character, density, and arrangement of the metal particles. By this means, as will be more fully set forth, I prevent the checks, cold-sets, and irregular condensation of the metal which attend and are unavoidable in the usual manner of making saw-teeth from blanks by the drophammer or stamping methods.

For a clearer understanding of my said invention, and to illustrate the best mode of employing and practicing the same, I shall refer to the accompanying drawings, in which- Figures 1, 2, and 3 are side elevations of the blank at different periods of. its formation. Fig. 4 is a plan of the blank. Figs. 5, 6, and 7 .show the matrix-carrying rolls in different positions. Fig. Sis a sectional enlarged view of the rolls. Fig. 9 is a plan view of the rolls and connecting-gear.

Similar letters of reference indicate correoccur.

From a strip of steel-plate of proper width and uniform thickness I out out a blank of the size and pattern illustrated by Fig. 1 in which the shank portion a has the thickness and quan tity of metal required for the shank of the finthe inside lines show the form and disposition of the metal when a tooth is formed from such a blank.

In the rolling operation to which I subject the blank, the shank a is held in a matrix, 0, provided in the periphery of one of a pair of rolls, D D, and is confined therein in such manner that the back part of the lower edge of the head portion 1) rests upon an anvil, J, while the fore partof the lower edge is held up clear of the-anvil, and then by means of a curved die secured in the other roll a rollingpressure is applied at and along the blank from heel to point by the rotation of the two rolls in time together, the peculiar form and action of the dies, as will be understood from the construction hereinafter particularly de scribed, operating to press the metal particles along the top of the blank first backward toward the heel, then downward diagonally into the neck, and then forward to form the point of the tooth from heel to point, and a condensation of metal to the degreedesired in the neck and upper portion of the tooth at the heel. To act upon this metal in the required manner-that is, to draw it backward and distrib ute it into the neck, to throw it forward to form the point, and to condense or compress it into the head and neck-I employ a set of rolling-dies and guiding-surfaces in one and a holding-matrix in another of a pair of rolls,

D D, of equal diameter. The two rolls are carried on horizontal journals E E, and are geared together, so as to rotate with the same motion and in fixed position with respect to each other. The recess It in the periphery of the roll D carries a die consisting of a curved roll in g-surlace, G, and upon either side a guid' ing-cheek, g g, projecting from the roll to present two curved rolling-edges for contact with and movement upon the opposing faces of two plates, l1 71 that are fixed in the recess H, in the opposite side, in between the two plates. In this last-named recess a block, I, fills up the space, excepting a portion that receives and holds the shank a of the blank. The outer end of this block is angular, forming the anvil .T, and it is made of a width to properly fall into the space between the two cheeks as they roll against the edges h 71 when the rolls rotate. hen the shank of the tooth is dropped into the recess, therefore, these blocks or plates form a matrix that confines all that portion of the blank above the anvil and regulates the lateral spread of the metal and the thickness of the tooth, while the curved die G, rolling over the outer edge of the blank, forces the head down against the anvil J, giving shape to the head and distributing the metal into the neck and throat portions of the tooth. The face of the die G projects above the face of the rolls, and is made on or approximating to a cycloidal curve, and so as to present a longer surface than the edge of the tooth against which it operates. \Vhile the two rolls turn uniformly together, therefore, the surface of such die has a faster movement than the edge of the blank carried in the face of the other roll, and instead of a simple rolling contact of these two surfaces the die has an increased movement, the effect of which is to act with a drawing-pressure against the blank. This throws the metal in longitudinal direc tion, instead of simply compressing it edgewise, as between two rolling surfaces, and thus the metal is drawn backward at the same time that it is compressed downward at the first half or portion of the pressure, and then as the die passes the center of the blank and is carried forward toward the. front, the drawing movement takes place in a forward direction, and sufficient metal is rolled forward over the anvil J to produce the point of the tooth. This construction and action of the dies and the matrix will be clearly understood from Figs. 5, 6, '7 of the drawings, where the dies are shown in the three positions of the first contact of the die with the heel of the blank, the position on the center, and the final relation of the two rolls as the end of the iorming operation is reached. These dies give a straight edge to the top of the head, and when discharged from the roll, the tooth is ready to be ground and sharpened at the point and to be milled andnotched at the shank, or otherwise provided with means or devices for securing them in the saw-plate.

In practice the rolls D l) are mounted in a suitable frame and driven by power applied through the medium of gearing to one of the rolls, and several recesses to receive sets of dies of various sizes being provided around the face of the rolls, the machine can be readily adjusted to make larger or smaller sizes of teeth, as desired.

Among the advantages to be derived from this method of making saw-teeth are the improved character of the teeth produced, their uniformity of structure, freedom from check and cold-sets, increased strength in and upon theline running diagonally from the throat to the heel, which I term the neck ofthe tooth, and, in addition, cheapness ofmanui'acture, rcsul ti 11g from the rapidity with which the blanks are finished, and economyin the use of stock.

freserve the right to make separate application for patent for the machine by which I carry out my process, and for the blank and article produced.

Having thus fully described my invention, what I claim, and desire to secure by Letters Patent, is-

The herein-described method or process of forming insertible saw-teeth. from steel plate, which consists in first cutting out a toothblank having an excess of metal breadthwise and a deficiency lengthwise in the area of its head as compared with the finished tooth to be produced, and then subjecting this blank in a heated state to a rolling-pressure from heel. to point between rolling dies or surfaces, whereby cold-sets and irregular condensations of the metal in the tooth are prevented, sub stantially as described.

In witness whereof I have hereunto set my hand and seal.

WILLIAM HAXVKINS. [c s.]

Attest:

lGnwn. GnA'r'riN, \VM. 1!. CLARK. 

